Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762180AbYGBJAN (ORCPT ); Wed, 2 Jul 2008 05:00:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752993AbYGBI7z (ORCPT ); Wed, 2 Jul 2008 04:59:55 -0400 Received: from relay1.sgi.com ([192.48.171.29]:46246 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752986AbYGBI7x (ORCPT ); Wed, 2 Jul 2008 04:59:53 -0400 Date: Wed, 2 Jul 2008 03:59:50 -0500 From: Robin Holt To: Andrew Morton Cc: Avi Kivity , Andrea Arcangeli , Linus Torvalds , Christoph Lameter , Jack Steiner , Robin Holt , Nick Piggin , Peter Zijlstra , kvm@vger.kernel.org, Kanoj Sarcar , Roland Dreier , Steve Wise , linux-kernel@vger.kernel.org, linux-mm@kvack.org, general@lists.openfabrics.org, Hugh Dickins , Rusty Russell , Anthony Liguori , Chris Wright , Marcelo Tosatti , Eric Dumazet , "Paul E. McKenney" , Izik Eidus , Rik van Riel Subject: Re: [PATCH 0 of 3] mmu notifier v18 for -mm Message-ID: <20080702085950.GV9696@sgi.com> References: <20080701214415.b3f93706.akpm@linux-foundation.org> <486B0B0F.5010605@qumranet.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <486B0B0F.5010605@qumranet.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1831 Lines: 42 On Wed, Jul 02, 2008 at 07:58:55AM +0300, Avi Kivity wrote: > Andrew Morton wrote: >> On Thu, 26 Jun 2008 02:26:56 +0200 Andrea Arcangeli wrote: >> >>> Full patchset including other XPMEM support patches can be found here: >>> >>> http://www.kernel.org/pub/linux/kernel/people/andrea/patches/v2.6/2.6.26-rc7/mmu-notifier-v18 >> >> I'm a bit concerned about merging the first three patches when there >> are eleven more patches of which some, afacit, are required to make >> these three actually useful. Committing these three would be signing a >> blank cheque. >> >> > > The first three are useful for kvm, gru, and likely drm and rdma nics. > > It is only xpmem which requires the other eleven patches. > >> Because if we hit strong objections with the later patches we end up in a >> cant-go-forward, cant-go-backward situation. SGI decided we need a functional GRU more than an enhanced XPMEM. We have, for 7 years now, told our customers that using XPMEM results in pages being permanently pinned and swap being disabled, and they have been accepting of that. We have also put other restrictions on what parts of the address space could be exported. It is not ideal, but it is functional. To work with distro kernels, we have requested 3 EXPORT_SYMBOL_GPL()s from SuSE (SLES-10) and 2 from RedHat (RHEL-5). With that and an LD_PRELOAD library, we can support most types of clone2()s safely and the documentation lists what is not supported (like mmap() into the middle of a region of memory that has been used for calculations). Thanks, Robin Holt -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/